package org.apache.lucene.search;

/**
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;
import org.apache.lucene.index.*;

final class ExactPhraseScorer extends PhraseScorer {

    ExactPhraseScorer(Weight weight, TermPositions[] tps, int[] positions, Similarity similarity, byte[] norms) {
        super(weight, tps, positions, similarity, norms);
    }

    protected final float phraseFreq() throws IOException {
        // sort list with pq
        for (PhrasePositions pp = first; pp != null; pp = pp.next) {
            pp.firstPosition();
            pq.put(pp); // build pq from list
        }
        pqToList(); // rebuild list from pq

        int freq = 0;
        do { // find position w/ all terms
            while (first.position < last.position) { // scan forward in first
                do {
                    if (!first.nextPosition())
                        return (float) freq;
                } while (first.position < last.position);
                firstToLast();
            }
            freq++; // all equal: a match
        } while (last.nextPosition());

        return (float) freq;
    }
}
